1. Field of the Invention
The present invention relates to a thin film supplying mechanism used in a paste supplier etc., employed in relief-plate printing devices and die bonders.
2. Prior Art
One of conventional relief-plate printing devices is constructed as shown in FIG. 2. Specifically, a recess 1a is formed in the upper surface of a original printing plate 1 which is made of glass or metal. The recess la has the depth of approximately 4 to 12 microns that corresponds to the thickness of ink film coated on an item 2 upon which printing is performed. This original printing plate 1 is positionally fixed on a table 3 which is moved horizontally by a driving means (not shown).
An ink pot 4 is installed above the original printing plate 1 so that the ink pot 4 can move up and down. This ink pot 4 consists of a blade 5, an ink tank 6 which is screw-connected with the blade 5 (so that the ink tank 6 can be freely removed from the blade 5), and a lid 7 which covers the top of the ink tank 6. An ink reservoir 5a is formed in the lower portion of the blade 5. An ink accommodating part 6a is formed in the upper portion of the ink tank 6, and a slit 6b which leads from the ink accommodating part 6a to the ink reservoir 5a is also formed in the ink tank 6.
A plate holder 11 which has a rubber relief printing plate 10 on its lower surface is installed above the right hand portion of the original printing plate 1. The plate holder 11 can be freely moved up and down. The item 2 to be printed is positioned beneath the plate holder 11.
Operation of the device will be described below:
The table 3 moves horizontally to the right (as shown in FIG. 2 (b)) with the ink pot 4 lowered and the lower end of the ink pot 4 pressed against the original printing plate 1 (as shown in FIG. 2(a)). With this movement, the ink 8 inside the ink reservoir 5a fills the recess 1a of the original printing plate 1.
Next, the plate holder 11 is lowered as indicated by the two-dot chain line. As a result, the rubber relief printing plate 10 comes into contact with the ink 8a of the recess 1a. Thus, the ink 8a adheres to the rubber relief printing plate 10.
The plate holder 11 then rises and the table 3 moves horizontally left as shown in FIG. 2(c). Afterward, the plate holder 11 is again lowered as indicated by the two-dot chain line. As a result, the rubber relief printing plate 10 is pressed against the item 2. Thus, the ink 8b adhering to the undersurface of the rubber relief printing plate 10 is transferred to the item 2. Then, the plate holder 11 is raised to its original position.
In the prior art described above, the recess 1a is formed in the original printing plate 1 by etching. Accordingly, when the thickness of the ink film applied to the item 2 is changed, the entire original printing plate 1 must be replaced. Accordingly, every time the original printing plate 1 is replaced, the lower-limit position and inclination of the ink pot 4 must be adjusted in accordance with the surface conditions (inclination) and thickness variations of the original printing plate 1. Otherwise, the lower surface of the ink pot 4 does not meet correctly with the upper surface of the original printing plate 1. Thus, a considerable amount of time is required for such adjustments.